I have been using a Summit Viper for several years now for both bow hunting and gun hunting. I shoot a Hoyt VTec which is about 35 inches ATA and have not had a problem with the bar getting in the way. When I shoot I just put my leading knee against the bar and then bend at the waist.

The seat o pants safety harness is an excellent product and I use it exclusively. Once you get used to it, you can barely tell it's on your body. I took a "Sharpie" marker and placed a big "L" on the left shoulder strap and a "R" on the right strap. This helps me untangle the harness quicker and in the dark.